Analysis Loss of Power In order for two generators to work effectively in parallel, it is essential that they maintain their speed and balance the electrical load between them. To achieve this, their respective governors and control systems must be compatible and capable of working together. The temporary genset was unable to balance the load automatically and there was not enough time for the crew to respond to the unforeseen loss of the No1SSG by manually taking up the load with the available potentiometer. When the diodes failed and caused No1SSG to lose voltage and trip off the board, the temporary genset could not respond to the sudden load change. The automatic control / protection system on the genset sensed an overload and under-voltage condition and shut down the engine, blacking out the vessel. The control system of the temporary genset installed at Liverpool was not totally compatible with the vessel's SSGs. When operated according to the onboard instructions, it could be physically parallelled with the other units. However, because of the characteristics of its control system, the temporary genset was unable to balance the load or respond to the sudden load change due to the failure of Noo1SSG, causing the vessel to blackout. Inspection and Intended Use of Temporary Generator Replacement equipment supplied to a vessel, even on a temporary basis, should provide an equivalent level of safety as the machinery it is replacing. The temporary genset installed on the CastPrivilege had been brought on board to replace the generating capacity lost due to the No2SSG being out of service. Although the vessel was originally designed to be run at sea with only one SSG , the growth in electrical load on the vessel, particularly with the carriage of reefer containers (which add additional electrical load), required two generators to be on line while at sea. Additionally, two generators were essential to ensure redundancy while operating in confined waters. At the time that the temporary genset was installed, the operator and ship's staff indicated to the Class surveyor that it would be run as a stand-alone unit only; it would not be parallelled with the vessel's remaining generators. As a result, the genset was not tested in parallel with the SSGs. Additionally, because of the size of the power cables installed, the output of the genset was initially limited to 400kW, even though this was insufficient to run the vessel under normal sea-load conditions. In this configuration, the failure of either of the remaining SSGs would have resulted in an inadequate supply of power being available to safely operate the vessel. Notwithstanding that the characteristics and power output of the temporary genset installation did not match that of the unit it was replacing, the installation was approved by Lloyd's. Subsequent to receiving Lloyd's approval of the installation on 05April2001, modifications were made to the temporary genset which enabled the unit to be parallelled with the SSGs. Detailed instructions were posted on the main switchboard (in Croatian) describing the temporary genset parallelling procedures to be followed by the engine room staff.3 As the managing operator did not advise Class of the changes to the installation, the classification society was deprived of the opportunity to conduct tests. Tests would have revealed that the genset was not capable of automatic load balancing with the other SSGs and was therefore, not safe to operate in parallel with the other SSGs. Consequently, the information provided by the managing owner to Class was insufficient to allow Lloyds to evaluate and make an informed decision as to whether the temporary genset installed on the vessel was capable of providing an equivalent level of performance and safety as the vessel's original equipment. The diodes failed and caused No1SSG to lose voltage and trip off the board. Characteristics of the temporary genset control system were such that it was unable to automatically balance the load or respond to the sudden load change caused by the failure of No1SSG, causing the ship to black-out. Notwithstanding that the characteristics and power output of the temporary genset installation did not match that of the unit it was replacing, the installation was approved by Lloyd's. Information provided by the managing owner to Class was insufficient to allow Lloyd's to evaluate and make an informed decision as to whether the temporary genset installed on the vessel was capable of providing an equivalent level of performance and safety as the vessel's original equipment.Findings as to Causes and Contributing Factors The diodes failed and caused No1SSG to lose voltage and trip off the board. Characteristics of the temporary genset control system were such that it was unable to automatically balance the load or respond to the sudden load change caused by the failure of No1SSG, causing the ship to black-out. Notwithstanding that the characteristics and power output of the temporary genset installation did not match that of the unit it was replacing, the installation was approved by Lloyd's. Information provided by the managing owner to Class was insufficient to allow Lloyd's to evaluate and make an informed decision as to whether the temporary genset installed on the vessel was capable of providing an equivalent level of performance and safety as the vessel's original equipment. Following the occurrence, a second Condition of Class was imposed by Lloyd's, stating that : Generator set on deck previously installed to replace stb'd lower generator to run on single mode (stand alone) till next port with port and stb'd upper generators readily on stand by. Vessel allowed to sail to Europe (one trip), where repairs will be carried out. A surveyor from the flag state (Bermuda) attended the vessel in November2001 and his report identifies safety measures in addition to their initial recommendations. A subsequent visit to the vessel in February2002 included a verification audit for the issuance of the Safety Management Certificate. Recommendations, which were found to have been implemented, included, inter alia:Safety Action Taken Following the occurrence, a second Condition of Class was imposed by Lloyd's, stating that : Generator set on deck previously installed to replace stb'd lower generator to run on single mode (stand alone) till next port with port and stb'd upper generators readily on stand by. Vessel allowed to sail to Europe (one trip), where repairs will be carried out. A surveyor from the flag state (Bermuda) attended the vessel in November2001 and his report identifies safety measures in addition to their initial recommendations. A subsequent visit to the vessel in February2002 included a verification audit for the issuance of the Safety Management Certificate. Recommendations, which were found to have been implemented, included, inter alia: